Update finsig_dryos.c to add display on/off stubs & fix s5is event proc detection.
Update finsig_vxworks.c to add display on/off stubs & improve event proc detection.
Add 'set_lcd_display' function for Lua & uBasic:
http://chdk.setepontos.com/index.php?topic=10551.msg104054#msg104054